Method and die for trimming blanks.



R. L WILCOX.

METHOD AND DIE FOR TRIMMING BLANKS.

APPLICATION HLED FEB. 26. IQIH.

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1:1` 1l LESTER WILCDX, OF WATERBURY. CONNEGIECUT, Aa'SlG-Itl'tlllt 'lltl BUlEtY FARBEL FOUNDRY AND MACHINE COMPANY, 01H' Wdlll'llthmh',

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METHOD IAND DIE FOB, TRMMILNG BLANKS.

`Speciication of Letters Patent.

Patented-l Felon ld, lltlllltll..

I Application led February 2e, 1918. Serial No. 219,171.

To all whom t may concern:

Be it known that l, RICHARD LESTER WIL- oox, a citizen of the United States, and a resident of Waterbury, county of New Haven, State of Connecticut, have invented certain new and useful Improvements in Methv ods and Dies for Trimmin Blanks, of which the followin is a specication.

My invention re ates more especially to methods and dies by which a blank can be given a polygonal' cross section such as the` square, hexagon or octagon shapes of bolt heads, nuts and the like or a many-sided shape of any kind, such for instance, as a circular section with flat sides, as is formed on shackle bolts and the like. llt will be understood that b polygonal ll` mean any such shape. AA lank may also be cut so as to have a circular section, and when l refer hereinafter to a trimmed section, it will be understood that I mean a section of any shape which has been cut or trimmed bythe dies, either entirely around it or on any particular portion.

@ne of the objects of my invention, among others, is to give a trimmed cross section to a blank without tearing the metal so that the Finished product will-have its faces smooth and of a uniform level throughout.

As the trimming of bolt heads and nuts has heretofore usually been carried out, the

blank has been passed through a die having a suitably shaped opening therein, in such a way that the cutting edges ofthe die enter f the blank by cutting for a short distance and then, the resistance to the cutting pressure having been suciently decreased, the remainin metal is practically torn from the blank, leaving the faces of the blank rough and in most cases, with de ressions below what should be the level o the face. For some classes of work, the bolts or nuts thus formed are undesirable because of their unsightly and unfinished appearance.

l have found that trimmed blankswith a very superior nish on the faces may be produced if the metal of the blank as it is being cut-away is not permitted to spread out, but is controlled so that the cutting pressure w-ill be maintained substantially constant throughout the operation.

'lhis general method may be carried out in different ways and l have found that the specic way which l am about to describe gives very satisfactory results.

The annexed drawings illustrate several of the many forms of dies with which my novel method may be carried out.

ln thev drawings, Figure l represents a form of die, together with a support there for, and a means whereby a blank may be forced into the die;

Figs. 2, 3 and Il represent, on 'anenlarged scale, the action of the die as the blank passes'through, Figs. 2 and 3 being sections on line 2-2 of Fig.

.in section.

The corresponding parts are referred to both in the drawings and in the specification by similar reference characters.

In the-drawings 10 represents an illustrative form of die which, in this instance, is of the solid type having a cylindrical recess ll extending for a short distance below its face and an opening l2, having a polygonal section (in this instance a hexagon) in alinement with the cylindrical opening l1. Preferably the polygonal opening has a maximum diameter slightly less than that of the cylindrical opening` ll and also preferably the bottom of the cylindrical opening 11 is slightly coned so as to produce the curved cutting edges l5 shown in Figs. l to Ll, inclusive. vPreferably the opening 1l will be shaped so as to give a proper clearance to the cutting edges 15.

Preferably the opening 11 is made slightly smaller in diameter' than the diameter of the head 13 of the blank which, in this instance, is represented as a bolt on which a beslagen head is to be formed.

By any suitable means, such as a plunger l/l,the head 13 is first forced into the circular opening ll. The beginning of this operation is shown in Fig. 2. The sharp outer edges of the die 10 around the circular opening l1 will reduce the diameter of the head 13 somewhat, as is shown in Fig. 3. lFha continued travel of the plunger will carry the head 13 past the cutting edges l5 ofthe polygonal opening 12. 'lhese cutting 5 and Fig. 4f being a section on line 1 4: of Fig. 5;

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llltl edges tit- A remove portions of the metal of the head 13, and as will "he obvious by an inspection of Fig. 4, this cut-away metal is controlled in the cylindrical opening 11 and is not permitted to diverge frornzthe cutting edges 15, as Would be the case if the cutting edges 15 were at the surface of the die l0.

The blank is pushed into the polygonal opening 12 a sufficient distance so that the bottom of the head will pass the cutting edges 15, and the polygonal head -is thus completely formed.

If desired, the blank can be pushed all the way through the die and dropped out at the rear, but preferably I stop the motion of the blank toward the left of Fig. 4 before the tion of the blank and the `vent the chip spreading to blankhas passed out of the polygonal opening 12, ,and then I return the blank toward the right of Fig. 4. This causes the bottom of the head to engage the chip 16 sufiiciently to eject the chip Aand clear the die for the next operation. A plunger 17 1s suitable for .giving this backward motion to the blank.

Approximately the same results may be obtained in the form of die shown in Fig. 6, in which a conical opening 1S is used instead of the cylindrical opening 11, the re mainder of the die being the same as 10. Then the chip is restrained and controlled in the conical opening although not to the same extent as When the form of die 10 is used.

While I have illustrated the formation of a hexagonal head on a bolt blank, it Will be understood that a polygonal form can be given to any blank by my novel method and the dies which I have illustrated.

It Will also be understood that if circular blanks are to be produced, then the opening 12 will be circular and of the diameter of the iinished blank. The chip will be controlled by the opening 1l in the same manner as when a polygonal cross section is produced.

While I have shown in F ig. 1, parts which obviously can be connected to a machine so as to carry out my novel method automatically, it Will be understood that the same results may be obtained by forcing the blank in any manner through dies embodying the novel structure which I have disclosed.

It will also be obvious that the same results are obtained if the die is forced over the blank instead of'forcing the blank into the die. When I refer to the forcing of the blank into the die, I mean the relative modie, Whether one or the other or both are moving.

While I have found it preferable to make the opening 11 cylindrical and somewhat smaller than the blank, this is not essential. The opening may be of any desired shape and size, so long as it is small enough to prepermit the die breaking o" the uncut material before the cut is completed. By making the opening smaller than the blank and not substantially larger than the opening 12, the metal of the chip Vis held closely to the blank so as to prevent the sudden breaking through of' the die and the consequent tearing of the surfaces.

It will be understood that preferably the polygonal openings l2 and i9 are made slightly pyramidal so as to relieve the cutting edges at the top of the openings.

It will also be understood that the cutting edges l5 may be formed on separate cutter bars held in, the die and my invention is not limited to the solid type of die which I have chosen for illustrative purposes.

I claim:

l. The method of giving a trimmed cross section to a blank, consisting of cutting from one end of the blank to the other and preventing the spreading of the chips while the cutting is taking place to prevent the tearing of the material of the blank as the cutting progresses.

2. The method of giving a trimmed cross section to a blank, consisting of cutting from one end of the blank to the other and compelling all of the removed material to flow in a direction substantially parallel with the direction of the cut.

3. The method of giving a trimmed cross section to a blank, consisting of forcing a blank into a recess of smaller area of cross section than the area of a cross section of the blank and of approximately the same con* tour and then into an opening adjacent the recess, to cause the material removed by the passage through the opening to remain in the recess.

4. The method of giving a trimmed cross section to a blank, consisting of forcing a blank into a recess, and then into an opening adjacent the recess, to cause the material removed by the passage through the opening to remain in the recess.

5. The method of giving a trimmed cross section to a blank, consisting of forcing a blank into a recess and then into a polygonal opening adjacent the recess, to cause the material removed by the passage through the polygonal opening to remain in the recess, an d then returning the blank through the opening and the recess, whereby the removed material is pushed out of the recess.

6. The method of giving a trimmed cross section to a blank, consisting of forcing a blank into a recess of slightly smaller diameter than the blank and of approximately the same contour and then into an adjacent opening Whose maximum diameter is not greater than that of the recess.

7. The method of giving a trimmed cross -section to a blank, consisting of forcing a blank into a recess eter than the blank, Whose maximum of slightly smaller diamand then into an opening diameter 1s not greater meneer then that ot the recess end then returning the-blank through the o ening und the recess, whereby the remove materiel is pushed out of the recess.

8. A die having en opening with cutting edges et one end of the openin and a recess adjacent the cutting edges an in alinement with the opening., the boundaries of the recess lying outside the boundaries of the opening. i

9. A die having an opening with cutting edges at one end of the opening and a cylin# dricalrecess adjacent the cutting edges and in elinement with the opening and having e. diameter not less than the maximum dismeter of the opening.

l0. A die having an opening with `cutting edges at one end of the opening in combination With'a recess adjacent the cutting edges and in slinement with the opening 4und Ineens whereby e, blonh msy be forced through the recess ond into the opening.

11. A die having en opening with cutting l edges et one end of the opening ond e recess ndJwoent the cutting edges sind in elinenient with the opening, Ineens whereby o blsnlr. may be forced the opening und Ineens whereby the :nished blank may be moved bsclrwnrdly out ot' ythe e. 12. A die having en opening With cutting edges at one end of the opening end s. recess adjacent the cutting edges end in etlinenient through the recess snol into 

